简介:Marineaccidentshavecausedimmensecasualtiesonvariouspartiesinshippingandshipbuildingindustries,includingfinancialandstructurallosses.Thissituationmakesshipaccidentbecomesacriticalsubjectinnavalarchitectureandmarinestructures,asitneedscontinuousassessmentandinvestigationtobroadeninsightanddataofcollisionandgroundingphenomena.Thepaperaimstoinvestigatestructuralconditionsofashiparrangedbydoublehullsystemunderaccidentalscenario,namelyshipgrounding.Fundamentalconceptofstructure-rockinteractioninpoweredhardgroundingisadoptedtodesignimpactconfigurationforcalculationusingfiniteelement(FE)simulation.Involvedentitiesaredefinedasthestructurerepresentedbytankervessel,andoceanicrockisdeployedastheindenterinanalysis.Calculationresultsindicatethatthecrashworthinesscapabilityofstructuralpartstrengthenedbylongitudinalgirderishigherthanotherselectedlocationsonthestructuresagainstrockpenetration.Localizedfloodingofstorageoilmayoccurduringrakingdamageisformedonstructuralpartbetweentwogirders.
简介:Usingfoursatellitedatasets(TOMS/SBUV,OMI,MLS,andHALOE),weanalyzetheseasonalvariationsofthetotalcolumnozone(TCO)anditszonaldeviation(TCO*),andrevealtheverticalstructureoftheOzoneLow(OV)overtheAsiancontinent.Ourprincipalfindingsare:(1)TheTCOovertheAsiancontinentreachesitsmaximuminthespringanditsminimumintheautumn.TheOzoneLowexistsfromMaytoSeptember.(2)TheOzoneLowhastwonegativecores,locatedinthelowerandtheupperstratosphere.Thelowercoreisnear30hPainthewinterand70hPaintheotherseasons.Theuppercorevariesfrom10hPato1hPaamongthefourseasons.(3)ThepositionoftheOzoneLowinthelowerandtheupperstratosphereovertheAsiancontinentshowsseasonalvariability.
简介:Uptothisdate,researchersarestillfacingdifficultiestoexpandthetechnologyofdirectmethanolfuelcells(DMFCs)becauseofthehighoverpotentialrequiredtooxidizethemethanolanditsrelativelypoorperformanceduetoCOpoisoningoftheleading-highcostanodecatalyst.Inlinewiththis,wehavesuccessfullymodifiedthemorphologicalstructureandcompositionoflowcostcobaltbased-metaloxides,MCo2O4(M=ZnandNi),withthesimpleandnobleuseofpolyvinylpyrrolidone(PVP)asgrowthmodifierandsurfacestabilizerduringthesynthesisofnanoparticlesinourpreviousreports,whichshownhighelectrocatalyticactivityandstrongstability.DuetothegoodperformanceofourPVPmodifiedMCo2O4towardspseudocapacitorandoxygenevolutionreactionapplications,wedecidedtoextendourresearchstudytomethanoloxidationreaction.Remarkably,PVPmodifiedNiCo2O4electrodedirectlygrownonnickelfoamsubstrateviaasimplehydrothermalprocessexhibitedbetterperformancecomparedwithPVPmodifiedZnCo2O4andNiCo2O4withoutPVP.Ithadobtainedaremarkablylowonsetpotentialof0.285Vandhighcurrentdensityof280mAcm-2,andshowngreatstabilityandhighpoisontoleranceduringacontinuousCVcyclingandChronoamperometrytest,whichattainedhighefficiencyof86.86%and98.52%,respectively.ThesepositiveresultsofPVPmodifiedNiCo2O4electrodetowardsMORmightbeattributedtoitshierarchical3Dnanostructureswithhighlymesoporoussurfaceandlargesurfaceareawhichmayhaveprovidednumerouselectroactivesites,andtheexceptionalcorrosionstabilityofNiCo2O4electrodeinalkalinesolution.
简介:Indouble-pulselaser-inducedbreakdownspectroscopy(DP-LIBS),thecollinearfemtoseconddouble-pulselaserconfigurationisexperimentallyinvestigatedwithdifferentinitialsampletemperaturesusingaTi:sapphirelaser.Theglasssampleisablatedtoproducetheplasmaspectroscopy.Duringtheexperiment,thedetectedspectrallinesincludetwoNa(I)lines(589.0nmand589.6nm)andoneCa(I)lineatthewavelengthof585.7nm.Theemissionlinesaremeasuredatroomtemperature(22°C)andthreehigherinitialsampletemperatures(Ts=100°C,200°C,and250°C).Theinter-pulsedelaytimerangesfrom-250psto250ps.Theinter-pulsedelaytimeandthesampletemperaturestronglyinfluencethespectralintensity,andthespectralintensitycanbesignificantlyenhancedbyincreasingthesampletemperatureandselectingtheoptimizedinter-pulsetime.Forthesameinter-pulsetimeof0ps(single-pulseLIBS),theenhancementratioisapproximately2.5atTs=200°CcomparedwiththatobtainedatTs=22°C.Forthesameinter-pulsetimeof150ps,theenhancementratiocanbeupto4atTs=200°CcomparedwiththatobtainedatTs=22°C.Thecombinedenhancementeffectsofthedifferentinitialsampletemperaturesandthedouble-pulseconfigurationinfemtosecondLIBSaremuchstrongerthanthatofthedifferentinitialsampletemperaturesorthedouble-pulseconfigurationonly.